Single potassium channels opened by opioids in rat locus ceruleus neurons.
Single potassium channels opened by opioids in rat locus ceruleus neurons.
复制标题
阿片类药物在大鼠蓝斑神经元中打开单钾通道。
DOI：
10.1073/pnas.86.9.3419
复制
发表时间：
1989
影响因子：
11.1
通讯作者：
North,RA
中科院分区：
文献类型：
--
作者：
Miyake,M;Christie,MJ;North,RA
通过单离子通道的电流记录在细胞附着配置从酶分离的新生大鼠蓝斑神经元。当选择性μ阿片受体激动剂Tyr-D-Ala-Gly-MePhe-Gly-ol在膜片钳电极中时，观察到电导约为45 pS的单一内向电流（在零移液管电位下测量，记录电极中有150 mM钾）。长时间的沉默，持续数秒到数分钟，将类似持续时间的活动时段分开。在这样的活动期间的通道的关闭时间的分布是最好的拟合两个指数函数（时间常数约为1和30毫秒）的总和，和通道开放的持续时间拟合由一个单一的指数函数;平均开放时间从2增加到120毫秒作为激动剂浓度的增加。在膜片钳记录电极外的神经元上施加高浓度阿片类药物时，未见通道活动，表明受体与钾通道之间存在密切偶联。当移液器中含有α 2肾上腺素受体激动剂或生长抑素时，也可观察到具有类似性质的单位电流。与以前的研究结果，结果表明，μ阿片受体，α 2肾上腺素受体，生长抑素受体可以直接耦合到膜钾通道通过GTP结合蛋白的局部中介作用。
Currents through single-ion channels were recorded in the cell-attached configuration from locus ceruleus neurons enzymatically dissociated from newborn rats. When the selective mu opioid receptor agonist Tyr-D-Ala-Gly-MePhe-Gly-ol was in the patch-clamp electrode, unitary inward currents were observed with conductance of approximately 45 pS (measured at zero pipette potential, with 150 mM potassium in the recording electrode). Long silences, lasting many seconds to minutes, separated periods of activity of similar durations. Within such activity periods the distribution of closed times of the channels was best fitted by the sum of two exponential functions (time constants approximately 1 and 30 ms), and the durations of channel openings were fit by a single exponential function; mean open time increased from 2 to 120 ms as agonist concentration increased. Channel activity was not seen when high concentrations of opioids were applied to the neuron outside the patch-clamp recording electrode, indicating intimate coupling between receptor and potassium channel. Unitary currents with similar properties were also seen when pipettes contained alpha 2 adrenoceptor agonists or somatostatin. Taken with previous findings, the results indicate that mu opioid receptors, alpha 2 adrenoceptors, and somatostatin receptors can couple directly to membrane potassium channels through the local intermediary action of a GTP binding protein.